Titanium oxide is the material having photo-catalysis. The photo-catalysis means that an active oxygen fragment such as OH radical and the like is formed on a surface of the titanium oxide when it is irradiated by light. The active oxygen fragment decomposes an organic substance present on the surface of the titanium oxide, and finally converts it into carbon dioxide and water. Therefore, the titanium oxide has recently been employed for removing organic substances present therearound such as odor, stain, fungus and the like.
The titanium oxide has generally been supported on a surface of an inorganic material such as tiles because the photo-catalysis of the titanium oxide is very active, and an organic material may be degraded remarkably if the organic material is brought into contact with the titanium oxide. If the titanium oxide is supported on an organic material, durability of the resulting material may become poor.
On the other hand, an organic material such as plastics and fibers is light-weight, easy to shape, and easy to handle. There is thus general needs for the material having photo-catalysis which is supported on an organic substrate.
Japanese Patent Laid Open Publication No. 171408/1995, and 265714/1995 disclose the method of employing an undecomposable resin such as a fluororesin and a silicone resin as a binder. Japanese Patent Laid Open Publication No. 157125/1991, and 213913/1995 disclose the method in which fine particles of titanium oxide is supported on a porous organic body. However, the titanium oxide directly contacts with an organic material such as a binder resin or a substrate even in the methods, and degradation of the material is not sufficiently prevented.
Japanese Patent Laid Open Publication No. 33988/1998 discloses the method in which titanium oxide particles are partially coated by alkyl silicate, and they are supported on an organic substrate. However, the photo-catalysis of the resulting material is poor because of a large amount of the alkyl silicate. Whereas, if the amount of the added alkyl silicate is reduced, contact area between the titanium oxide and the organic substrate becomes large, and durability of the resulting material becomes poor.